Corner clamp



FIG. 1 is a top, front, left perspective view of a corner clamp, showing my new design;

FIG. 2 is a top, rear, right perspective view thereof; and,

FIG. 3 is a bottom, front, right perspective view thereof.

The broken lines illustrate portions of the corner clamp that form no part of the claimed design. 

CLAIM The ornamental design for a corner clamp, as shown and described. 